Communities and local governments across the country face a period of extreme uncertainty Whether or not COVID-19 is quickly contained, changes in consumer dem

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Comparative genetic analysis of the novel coronavirus (2019-nCoV/SARS-CoV-2) receptor ACE2 in different populations

Since the initial reports of coronavirus disease 2019 (COVID-19) in China in late 2019, infections from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have spread rapidly, resulting in a global pandemic that has caused millions of deaths. Initially, the large number of infected people required the direction of global healthcare resources to provide supportive care for the acutely ill population in an attempt to reduce mortality. While clinical trials for safe and effective antiviral agents are ongoing, and vaccine development programs are being accelerated, long-term sequelae of SARS-CoV-2 infection have become increasingly recognized and concerning. Although the upper and lower respiratory tracts are the main sites of entry of SARS-CoV-2 into the body, resulting in COVID-19 pneumonia as the most common presentation, acute lung damage may be followed by pulmonary fibrosis and chronic impairment of lung function, with impaired quality of life. Also, increasing reports have shown that SARS-CoV-2 infection involves the central nervous system (CNS) and the peripheral nervous system (PNS) and directly or indirectly damages neurons, leading to long-term neurological sequelae. This review aims to provide an update on the mechanisms involved in the development of the long-term sequelae of SARS-CoV-2 infection in the 3 main areas of lung injury, neuronal injury, and neurodegenerative diseases, including Alzheimer disease, Parkinson disease, and multiple sclerosis, and highlights the need for patient monitoring following the acute stage of infection with SARS-CoV-2 to provide a rationale for the prevention, diagnosis, and management of these potential long-term sequelae.

Long-Term Respiratory and Neurological Sequelae of COVID-19.

In recent months it has emerged that the novel coronavirus-responsible for the COVID-19 pandemic-causes reduction of smell and taste in a large fraction of patients. The chemosensory deficits are often the earliest, and sometimes the only signs in otherwise asymptomatic carriers of the SARS-CoV-2 virus. The reasons for the surprisingly early and specific chemosensory dysfunction in COVID-19 are now beginning to be elucidated. In this hypothesis review, we discuss implications of the recent finding that the prevalence of smell and taste dysfunction in COVID-19 patients differs between populations, possibly because of differences in the spike protein of different virus strains or because of differences in the host proteins that enable virus entry, thus modifying infectivity. We review recent progress in defining underlying cellular and molecular mechanisms of the virus-induced anosmia, with a focus on the emerging crucial role of sustentacular cells in the olfactory epithelium. We critically examine the current evidence whether and how the SARS-CoV-2 virus can follow a route from the olfactory epithelium in the nose to the brain to achieve brain infection, and we discuss the prospects for using the smell and taste dysfunctions seen in COVID-19 as an early and rapid diagnostic screening tool.

https://journals.sagepub.com/doi/pdf/10.1177/1073858420956905

Anosmia in COVID-19: Underlying Mechanisms and Assessment of an Olfactory Route to Brain Infection.

Anosmia is one of the most prevalent symptoms of SARS-CoV-2 infection during the COVID-19 pandemic However, the cellular mechanism behind the sudden loss of smell has not yet been investigated The initial step of odour detection takes place in the pseudostratified olfactory epithelium (OE) mainly composed of olfactory sensory neurons surrounded by supporting cells known as sustentacular cells The olfactory neurons project their axons to the olfactory bulb in the central nervous system offering a potential pathway for pathogens to enter the central nervous system by bypassing the blood brain barrier In the present study, we explored the impact of SARS-CoV-2 infection on the olfactory system in golden Syrian hamsters We observed massive damage of the OE as early as 2 days post nasal instillation of SARS-CoV-2, resulting in a major loss of cilia necessary for odour detection These damages were associated with infection of a large proportion of sustentacular cells but not of olfactory neurons, and we did not detect any presence of the virus in the olfactory bulbs We observed massive infiltration of immune cells in the OE and lamina propria of infected animals, which may contribute to the desquamation of the OE The OE was partially restored 14 days post infection Anosmia observed in COVID-19 patient is therefore likely to be linked to a massive and fast desquamation of the OE following sustentacular cells infection with SARS-CoV-2 and subsequent recruitment of immune cells in the OE and lamina propria

Massive transient damage of the olfactory epithelium associated with infection of sustentacular cells by SARS-CoV-2 in golden Syrian hamsters.

A significant proportion of people who test positive for COVID-19 have chemosensory deficits. However, the reported prevalence of these deficits in smell and taste varies widely, and the reason for...

Prevalence of Chemosensory Dysfunction in COVID-19 Patients: A Systematic Review and Meta-analysis Reveals Significant Ethnic Differences.

Background As reported by increasing literature, a significant number of patients with SARS-CoV-2 infection developed smell/taste disorders. Aim of this study is to determine the prevalence and severity of these symptoms among laboratory-confirmed SARS-CoV-2 patients. Secondary objective is to determine their onset/recovery time. Methods This cross-sectional study was conducted from March 10 to 30, 2020 at Novara University Hospital during the COVID-19 Italian outbreak. The 355 enrolled patients answered a questionnaire at 14th (or more) days after proven infection. Results The overall population prevalence of both smell/taste or one of the two disorders was 70%. They were first symptoms in 31 (8,7%) patients. Most patients reported a complete loss that in half of the cases (49.5%) was fully recovered after 14 days, with a median recovery time of 10 days. Conclusion This study confirms a high prevalence of smell/taste disorders in COVID-19 infection with self-recovery for half cases after about 2 weeks.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/hed.26288

Miriam Gatto

Papers

Smell and taste disorders during COVID-19 outbreak: Cross-sectional study on 355 patients.